Shane and Frances McShane, the parents of Saoirse McShane (22), spoke out after an inquest into her death heard she had consumed the drug at a music festival.

Just 48 hours later she was dead, having fallen sick before suffering a heart attack.

"We would never have thought that ecstasy could have had such an effect on someone who was so healthy," her father said. "We're just devastated."

The family said they were also shocked by the revelation that a toxic attack on their daughter's system apparently began from the very moment she consumed the tiny quantity of the drug.

Ms McShane, of South Mall, Cork, died on September 6 last year -- just over 48 hours after she took half an ecstasy tablet at the Electric Picnic music festival in Stradbally, Co Laois.

The inquest in Cork was told that different people can have radically different reactions to the drug. Assistant state pathologist Dr Margaret Bolster said the ecstasy -- even such a small amount -- triggered a toxic reaction in the young woman's system that ended in cardiac failure.

"Some people can take ecstasy and feel grand but others can take it and have a lethal reaction. It is rare but medically recognised. Everyone who takes these tablets takes the risk," she explained.

Coroner Dr Myra Cullinane was told Ms McShane was healthy and had no previous heart conditions. She had met friends at the Electric Picnic on September 4 -- but later complained of feeling unwell and drove back to Cork from Laois.

One female friend, said she had met Saoirse and they shared an ecstasy pill.

"She seemed fine and she took no other drugs that I'm aware of," she said.

A male friend said Ms McShane complained of feeling unwell on the trip back to Cork the following evening.

When she woke on September 6, she complained of not having been able to sleep -- and having bad cramps, breathlessness and dizziness. She went to a GP but didn't inform them she had taken ecstasy.

She returned to her flat where her symptoms became worse and her alarmed flat mate called an ambulance.

The young woman collapsed as she was being brought to an ambulance. She had suffered a heart attack, and despite efforts to revive her, was pronounced dead a short time later.

Dr Cullinane returned a verdict of death by misadventure.

"Saoirse had a rare side effect -- the toxicity of the ecstasy in her system caused acute cardio failure. This is such a very sad case," she said.

Ms McShane is survived by her parents and siblings Rohan, Fionn, Oisin, Rory, Katie and Aoife.